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A MAXIMIZATION PROBLEM  39


                                      Mathematical Statement of the GulfGolf Problem
                      Try Problem 13 to test  The mathematical statement or mathematical formulation of the GulfGolf problem
                      your ability to formulate a  is now complete. We succeeded in translating the objective and constraints of the
                      mathematical model for a
                      maximization linear  problem into a set of mathematical relationships referred to as a mathematical
                      programming problem  model. The complete mathematical model for the problem is then:
                      with less-than-or-equal-
                      to constraints.                 Max  10S þ 9D
                                                      subject to (s.t.)
                                                            7
                                                            / 10 S þ 1D   630 Cutting and dyeing
                                                            1 / 2 S þ / 6 D   600 Sewing
                                                                 5
                                                                 2
                                                             1S þ / 3 D   708 Finishing
                                                           7     1
                                                            / 10 S þ / 4 D   135 Inspection and packaging
                                                                S; D   0
                                      However, because we shall be carrying out a variety of mathematical operations
                                      using these data it will be useful to show the formulation in decimal notation rather
                                      than fractional, giving:


                                                         Max  10S þ 9D
                                                         s:t:
                                                              0:7S þ 1D     630
                                                              0:5S þ 0:8333D   600
                                                              1S  þ 0:6667D   708
                                                              0:1S þ 0:25D    135
                                                                       S; D   0                         (2:6)


                                         Our job now is to find the product mix (i.e., the combination of S and D) that
                                      satisfies all the constraints and, at the same time, yields the maximum possible value
                                      for the objective function. Once these values are calculated, we will have found the
                                      optimal solution to the problem.
                                         This mathematical model of the problem is a linear programming model,or
                                      linear programme. The problem has the objective and constraints that, as we said
                                      earlier, are common properties of all linear programmes. But what is the special
                                      feature of this mathematical model that makes it a linear programme? The special
                                      feature that makes it a linear programme is that the objective function and all
                                      constraint functions (the left-hand sides of the constraint inequalities) are linear
                                      functions of the decision variables.
                                         Mathematical functions in which each variable appears in a separate term and
                      Try Problem 1 to test  is raised to the first power are called linear functions. The objective function
                      your ability to recognize  (10S +9D) is linear because each decision variable appears in a separate term
                      the types of    and has an exponent of 1. The amount of production time required in the
                      mathematical
                      relationships that can be  cutting and dyeing department (0.7S +1D) is also a linear function of the
                      found in a linear  decision variables for the same reason. Similarly, the functions on the left-hand
                      programme.      side of all the constraint inequalities (the constraint functions) are linear func-
                                      tions. Thus, the mathematical formulation of this problem is referred to as a
                                      linear programme.
                                         Linear programming has nothing to do with computer programming. The use of
                                      the word programming here means ‘choosing a course of action’. Linear program-
                                      ming involves choosing a course of action when the mathematical model of the
                                      problem contains only linear functions.





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